The present invention is directed to an apparatus for generating a character pattern signal, and in particular to an apparatus which generates a character pattern signal utilizing a dot pattern formed from outline data which are stored as bits of outline information.
In present word processors and the like, in order to enhance print quality of a character pattern, the number of dots which form the character pattern need to be increased. A conventional manner for obviating this problem has been through the introduction of an outline system. As shown in FIG. 5 of the drawings, in the outline system, the outline of a character is divided into a plurality of regions extending about the perimeter of a character such as regions, J.sub.0, J.sub.1, J.sub.2. The coordinates of an initial starting point and a terminal point for each region J.sub.0, J.sub.1, J.sub.2 are stored as data, and this data is converted to dot pattern data during the displaying of a character by the word processor.
As shown in FIG. 6, a conic spline represented as the curve J.sub.n approximates the curve J.sub.2 (FIG. 5) which is a portion of a character outline. Curve J.sub.n has an initial point A at coordinate address X.sub.A, Y.sub.A and a terminal point B having a coordinate address X.sub.B, Y.sub.B. A line F extends tangentially to curve J.sub.n at initial point A. A second line G extends tangentially to curve J.sub.n from terminal point B. A control point C having a coordinate address X.sub.C, Y.sub.C is defined at the intersection of lines F and G. A line segment H connecting at a midpoint D of line F and a midpoint E of line G contacts conic spline curve J.sub.n at an intermediate point M having a coordinate address X.sub.M, Y.sub.M. Therefore, the outline of conic spline curve J.sub.n of conic spline curve J.sub.n can be reproduced utilizing a conic spline function by storing coordinates (X.sub.A, Y.sub.A), (X.sub.B, Y.sub.B), (X.sub.C, Y.sub.C) and (X.sub.M, Y.sub.M) of starting point A, terminal point B, control point C and intermediate point M as the data indicating the outline. Storage of the conic spline in such a manner allows expansion and reduction of the size of the character to be printed which improves character quality by reducing the quantity of data to be stored. However, the prior art suffers from the disadvantage that when a character pattern having a standard size as stored is to be compressed, the print quality of the reduced character becomes deteriorated. Specifically, as seen in FIG. 4a, dots F become separated by a space E from the remaining body G of the character where a skipped part of the outline exists. Accordingly, it is desired to provide a character pattern signal generator which utilizes character outline data which may reduce the size of the character without deteriorating print quality.